#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/kobject.h>
+#include <linux/bug.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
+#include "sysfs.h"
+
+static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj);
+
+static u64 get_features(struct btrfs_fs_info *fs_info,
+ enum btrfs_feature_set set)
+{
+ struct btrfs_super_block *disk_super = fs_info->super_copy;
+ if (set == FEAT_COMPAT)
+ return btrfs_super_compat_flags(disk_super);
+ else if (set == FEAT_COMPAT_RO)
+ return btrfs_super_compat_ro_flags(disk_super);
+ else
+ return btrfs_super_incompat_flags(disk_super);
+}
+
+static void set_features(struct btrfs_fs_info *fs_info,
+ enum btrfs_feature_set set, u64 features)
+{
+ struct btrfs_super_block *disk_super = fs_info->super_copy;
+ if (set == FEAT_COMPAT)
+ btrfs_set_super_compat_flags(disk_super, features);
+ else if (set == FEAT_COMPAT_RO)
+ btrfs_set_super_compat_ro_flags(disk_super, features);
+ else
+ btrfs_set_super_incompat_flags(disk_super, features);
+}
+
+static int can_modify_feature(struct btrfs_feature_attr *fa)
+{
+ int val = 0;
+ u64 set, clear;
+ switch (fa->feature_set) {
+ case FEAT_COMPAT:
+ set = BTRFS_FEATURE_COMPAT_SAFE_SET;
+ clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
+ break;
+ case FEAT_COMPAT_RO:
+ set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
+ clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
+ break;
+ case FEAT_INCOMPAT:
+ set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
+ clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
+ break;
+ default:
+ BUG();
+ }
+
+ if (set & fa->feature_bit)
+ val |= 1;
+ if (clear & fa->feature_bit)
+ val |= 2;
+
+ return val;
+}
+
+static ssize_t btrfs_feature_attr_show(struct kobject *kobj,
+ struct kobj_attribute *a, char *buf)
+{
+ int val = 0;
+ struct btrfs_fs_info *fs_info = to_fs_info(kobj);
+ struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
+ if (fs_info) {
+ u64 features = get_features(fs_info, fa->feature_set);
+ if (features & fa->feature_bit)
+ val = 1;
+ } else
+ val = can_modify_feature(fa);
+
+ return snprintf(buf, PAGE_SIZE, "%d\n", val);
+}
+
+static ssize_t btrfs_feature_attr_store(struct kobject *kobj,
+ struct kobj_attribute *a,
+ const char *buf, size_t count)
+{
+ struct btrfs_fs_info *fs_info;
+ struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
+ struct btrfs_trans_handle *trans;
+ u64 features, set, clear;
+ unsigned long val;
+ int ret;
+
+ fs_info = to_fs_info(kobj);
+ if (!fs_info)
+ return -EPERM;
+
+ ret = kstrtoul(skip_spaces(buf), 0, &val);
+ if (ret)
+ return ret;
+
+ if (fa->feature_set == FEAT_COMPAT) {
+ set = BTRFS_FEATURE_COMPAT_SAFE_SET;
+ clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR;
+ } else if (fa->feature_set == FEAT_COMPAT_RO) {
+ set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET;
+ clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR;
+ } else {
+ set = BTRFS_FEATURE_INCOMPAT_SAFE_SET;
+ clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR;
+ }
+
+ features = get_features(fs_info, fa->feature_set);
+
+ /* Nothing to do */
+ if ((val && (features & fa->feature_bit)) ||
+ (!val && !(features & fa->feature_bit)))
+ return count;
+
+ if ((val && !(set & fa->feature_bit)) ||
+ (!val && !(clear & fa->feature_bit))) {
+ btrfs_info(fs_info,
+ "%sabling feature %s on mounted fs is not supported.",
+ val ? "En" : "Dis", fa->kobj_attr.attr.name);
+ return -EPERM;
+ }
+
+ btrfs_info(fs_info, "%s %s feature flag",
+ val ? "Setting" : "Clearing", fa->kobj_attr.attr.name);
+
+ trans = btrfs_start_transaction(fs_info->fs_root, 1);
+ if (IS_ERR(trans))
+ return PTR_ERR(trans);
+
+ spin_lock(&fs_info->super_lock);
+ features = get_features(fs_info, fa->feature_set);
+ if (val)
+ features |= fa->feature_bit;
+ else
+ features &= ~fa->feature_bit;
+ set_features(fs_info, fa->feature_set, features);
+ spin_unlock(&fs_info->super_lock);
+
+ ret = btrfs_commit_transaction(trans, fs_info->fs_root);
+ if (ret)
+ return ret;
+
+ return count;
+}
+
+static umode_t btrfs_feature_visible(struct kobject *kobj,
+ struct attribute *attr, int unused)
+{
+ struct btrfs_fs_info *fs_info = to_fs_info(kobj);
+ umode_t mode = attr->mode;
+
+ if (fs_info) {
+ struct btrfs_feature_attr *fa;
+ u64 features;
+
+ fa = attr_to_btrfs_feature_attr(attr);
+ features = get_features(fs_info, fa->feature_set);
+
+ if (can_modify_feature(fa))
+ mode |= S_IWUSR;
+ else if (!(features & fa->feature_bit))
+ mode = 0;
+ }
+
+ return mode;
+}
+
+BTRFS_FEAT_ATTR_INCOMPAT(mixed_backref, MIXED_BACKREF);
+BTRFS_FEAT_ATTR_INCOMPAT(default_subvol, DEFAULT_SUBVOL);
+BTRFS_FEAT_ATTR_INCOMPAT(mixed_groups, MIXED_GROUPS);
+BTRFS_FEAT_ATTR_INCOMPAT(compress_lzo, COMPRESS_LZO);
+BTRFS_FEAT_ATTR_INCOMPAT(compress_lzov2, COMPRESS_LZOv2);
+BTRFS_FEAT_ATTR_INCOMPAT(big_metadata, BIG_METADATA);
+BTRFS_FEAT_ATTR_INCOMPAT(extended_iref, EXTENDED_IREF);
+BTRFS_FEAT_ATTR_INCOMPAT(raid56, RAID56);
+BTRFS_FEAT_ATTR_INCOMPAT(skinny_metadata, SKINNY_METADATA);
+
+static struct attribute *btrfs_supported_feature_attrs[] = {
+ BTRFS_FEAT_ATTR_PTR(mixed_backref),
+ BTRFS_FEAT_ATTR_PTR(default_subvol),
+ BTRFS_FEAT_ATTR_PTR(mixed_groups),
+ BTRFS_FEAT_ATTR_PTR(compress_lzo),
+ BTRFS_FEAT_ATTR_PTR(compress_lzov2),
+ BTRFS_FEAT_ATTR_PTR(big_metadata),
+ BTRFS_FEAT_ATTR_PTR(extended_iref),
+ BTRFS_FEAT_ATTR_PTR(raid56),
+ BTRFS_FEAT_ATTR_PTR(skinny_metadata),
+ NULL
+};
+
+static const struct attribute_group btrfs_feature_attr_group = {
+ .name = "features",
+ .is_visible = btrfs_feature_visible,
+ .attrs = btrfs_supported_feature_attrs,
+};
+
+static void btrfs_release_super_kobj(struct kobject *kobj)
+{
+ struct btrfs_fs_info *fs_info = to_fs_info(kobj);
+ complete(&fs_info->kobj_unregister);
+}
+
+static struct kobj_type btrfs_ktype = {
+ .sysfs_ops = &kobj_sysfs_ops,
+ .release = btrfs_release_super_kobj,
+};
+
+static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
+{
+ if (kobj->ktype != &btrfs_ktype)
+ return NULL;
+ return container_of(kobj, struct btrfs_fs_info, super_kobj);
+}
+
+void btrfs_sysfs_remove_one(struct btrfs_fs_info *fs_info)
+{
+ kobject_del(&fs_info->super_kobj);
+ kobject_put(&fs_info->super_kobj);
+ wait_for_completion(&fs_info->kobj_unregister);
+}
+
+const char * const btrfs_feature_set_names[3] = {
+ [FEAT_COMPAT] = "compat",
+ [FEAT_COMPAT_RO] = "compat_ro",
+ [FEAT_INCOMPAT] = "incompat",
+};
+
+#define NUM_FEATURE_BITS 64
+static char btrfs_unknown_feature_names[3][NUM_FEATURE_BITS][13];
+static struct btrfs_feature_attr btrfs_feature_attrs[3][NUM_FEATURE_BITS];
+
+static void init_feature_attrs(void)
+{
+ struct btrfs_feature_attr *fa;
+ int set, i;
+
+ BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names) !=
+ ARRAY_SIZE(btrfs_feature_attrs));
+ BUILD_BUG_ON(ARRAY_SIZE(btrfs_unknown_feature_names[0]) !=
+ ARRAY_SIZE(btrfs_feature_attrs[0]));
+
+ for (i = 0; btrfs_supported_feature_attrs[i]; i++) {
+ struct btrfs_feature_attr *sfa;
+ struct attribute *a = btrfs_supported_feature_attrs[i];
+ sfa = attr_to_btrfs_feature_attr(a);
+ fa = &btrfs_feature_attrs[sfa->feature_set][sfa->feature_bit];
+
+ fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name;
+ }
+
+ for (set = 0; set < FEAT_MAX; set++) {
+ for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
+ char *name = btrfs_unknown_feature_names[set][i];
+ fa = &btrfs_feature_attrs[set][i];
+
+ if (fa->kobj_attr.attr.name)
+ continue;
+
+ snprintf(name, 13, "%s:%u",
+ btrfs_feature_set_names[set], i);
+
+ fa->kobj_attr.attr.name = name;
+ fa->kobj_attr.attr.mode = S_IRUGO;
+ fa->feature_set = set;
+ fa->feature_bit = 1ULL << i;
+ }
+ }
+}
+
+static u64 supported_feature_masks[3] = {
+ [FEAT_COMPAT] = BTRFS_FEATURE_COMPAT_SUPP,
+ [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
+ [FEAT_INCOMPAT] = BTRFS_FEATURE_INCOMPAT_SUPP,
+};
+
+static int add_unknown_feature_attrs(struct btrfs_fs_info *fs_info)
+{
+ int set;
+
+ for (set = 0; set < FEAT_MAX; set++) {
+ int i, count, ret, index = 0;
+ struct attribute **attrs;
+ struct attribute_group agroup = {
+ .name = "features",
+ };
+ u64 features = get_features(fs_info, set);
+ features &= ~supported_feature_masks[set];
+
+ count = hweight64(features);
+
+ if (!count)
+ continue;
+
+ attrs = kcalloc(count + 1, sizeof(void *), GFP_KERNEL);
+
+ for (i = 0; i < NUM_FEATURE_BITS; i++) {
+ struct btrfs_feature_attr *fa;
+
+ if (!(features & (1ULL << i)))
+ continue;
+
+ fa = &btrfs_feature_attrs[set][i];
+ attrs[index++] = &fa->kobj_attr.attr;
+ }
+
+ attrs[index] = NULL;
+ agroup.attrs = attrs;
+
+ ret = sysfs_merge_group(&fs_info->super_kobj, &agroup);
+ kfree(attrs);
+ if (ret)
+ return ret;
+ }
+ return 0;
+}
/* /sys/fs/btrfs/ entry */
static struct kset *btrfs_kset;
+int btrfs_sysfs_add_one(struct btrfs_fs_info *fs_info)
+{
+ int error;
+
+ init_completion(&fs_info->kobj_unregister);
+ fs_info->super_kobj.kset = btrfs_kset;
+ error = kobject_init_and_add(&fs_info->super_kobj, &btrfs_ktype, NULL,
+ "%pU", fs_info->fsid);
+
+ error = sysfs_create_group(&fs_info->super_kobj,
+ &btrfs_feature_attr_group);
+ if (error)
+ goto failure;
+
+ error = add_unknown_feature_attrs(fs_info);
+ if (error)
+ goto failure;
+
+ return 0;
+failure:
+ btrfs_sysfs_remove_one(fs_info);
+ return error;
+}
+
int btrfs_init_sysfs(void)
{
+ int ret;
btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
if (!btrfs_kset)
return -ENOMEM;
+
+ init_feature_attrs();
+
+ ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
+ if (ret) {
+ kset_unregister(btrfs_kset);
+ return ret;
+ }
+
return 0;
}
void btrfs_exit_sysfs(void)
{
+ sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
kset_unregister(btrfs_kset);
}
projects / cascardo / linux.git / blobdiff